Boeing has announced that its 737 MAX aircraft has reached the firm concept stage. The program is now set to transition to finalizing configuration details by the middle of 2013. The aircraft is on track to deliver the first model in 2017 to carriers around the world.

The 737 MAX will be a single-aisle aircraft and will use new LEAP-1B engines from CFM International. The aircraft also has a redesigned tail cone and Advanced Technology winglets. Those changes and others will allow for up to a 13 percent reduction in fuel use.

In addition, Honeywell will supply the electronic bleed air system for the aircraft, while Rockwell Collins will supply four large-format displays for the flight deck.

The Boeing design team has also defined the high-speed aerodynamic lines for the 737 MAX using analysis and testing conducted in both high and low speed wind tunnels. A further refined shape for the aircraft eliminated the need for small bump on the nose gear door that was seen in early designs.